Lipase is an enzyme which decomposes fat and fatty acid esters and is extracted from internal organs of animals or produced by cultivating microorganisms. However, conventional lipase is unstable at a high temperature, especially at a temperature higher than 50.degree. C. and stable only in a narrow pH range. Therefore, it is not suitable for industrial use.
For example, Japanese Patent Publication No. 42266/1981 discloses a process for production of lipase which comprises cultivating Rhizopus chinensis HI-S in a culture medium and recovering lipase from the culture. Lipase obtained by this process, however, loses its activity at a temperature higher than 50.degree. C. and is stable only in a pH range of 4.0 to 8.0.
As a result of the extensive study, it has now been found that a certain specific strain belonging to the genus Rhizopus produces lipase having improved heat-resistance and pH stability.